Calibration check input mode refinements

[CaverBruce]

Further to #122 (not sure how to reopen it) Quick work to v1.3.11, took me a moment to work out what a 'calibration check' input mode might be, despite our recent conversation! I suggest that it be renamed 'splays only', as that will be more generically applicable and meaningful to the general user I expect.

Also, I notice that after taking some shots in calibration check/splays only and swapping to 'forward' that the last few splay shots are pushed ahead of the new leg and attached to the new station. On each new leg, one of the pushed ahead splays is dropped, presumably to further up the table to the station they were originally taken from - 2 in this case (or lost??). In the screenshot with station 5 in it, a single splay from 5 shows the situation with only one splay pushed ahead. Presumably with one more forward leg taken, that splay too will be dropped back to station 2 - I did not take it that far however.

BTW, I checked the backsight mode, and it seems to work fine. However Fore/Backsights appears to only give foresights, so still something missing there in the behaviour or in my understanding.

[richsmith]

OK, you're probably right about the wording. I'll change in the next update. Not sure I follow what is happening with the mode switching, will have to experiment.